Cook and the rest of the Apple team have repeatedly said that China's going to be one of the company's most important markets in the coming years. Apple already has deals with China Telecom (CHA) and China Unicom (CHU) , but getting a deal with China Mobile would transform Apple's place in the Far East.

China Mobile is by far the largest mobile carrier in China, with more than 700 million users. According to Evercore Partners analyst Rob Cihra, more than 82 million of those users have 3G plans. One of the reasons why Apple and China Mobile have not been able to get together is the lack of infrastructure and support for the iPhone on China Mobile's end. But that's changing as the Chinese carrier tests its 4G network and cedes market share of higher-end mobile users to its smaller rivals.

"We think China Mobile could be starting to 'need' the iPhone more, since it has seen its 3G market share erode by -7 percent to 37 percent since 2011 vs. China Telecom+Unicom having gained +7 percent to 63 percent," Cihra wrote in a recent research report.

China Telecom and China Unicom have had the iPhone 5 since mid-December but China Mobile has not been able to stem the market share decline with Apple's latest and greatest phone. If China Mobile were to sign a deal making the iPhone official on its network (there are reports of as many as 15 million iPhones on its network), this would be a huge deal for both companies.

On Apple's fiscal fourth-quarter earnings call, Cook noted Chinese revenue was up 26% year over year to $5.7 billion. The iPhone 5 has not officially been granted network access yet, but with deals with China Telecom, China Unicom and potentially China Mobile on the way it's widely expected this number will be much higher in the coming months.

Apple has done well in China, but perhaps not as well as some of its rivals, including Samsung, ZTE, and other device makers entrenched in the world's most populous nation. Completing a deal with China Mobile would allow Apple to grow its market share and presence around the world.